LIFE HISTORIES OF FAMILIAR PLANTS 



by the leaves with the watery sap supplied by the 

 root, the ultimate product of this combination 

 — in which the energy of sunlight is interwoven — 

 being energy-yielding starches, and similar food 

 materials; that will build and sustain a young and 

 growing plant. 



The nurse-leaves being spread out to the sun- 

 light, therefore, the machinery of growth, as it 

 were, comes into motion, and, consequently, 

 further development proceeds apace. In Fig. lo 

 (Plate 7) the young plant is shown as it appears 

 about the middle of April. It will be observed 

 that the central part is now occupied with two 

 leaves— the first pair of true leaves of the young 

 sycamore tree — and between these leaves is a tiny 

 bud where other leaves are being formed. 



Later these leaves will open out, and their 

 place be then occupied with two younger ones. 

 In Fig. II (Plate 8) this further development, is 

 shown. It should now be noticed that the nurse- 

 leaves are shrivelling up, and soon they will fall 

 away. The young plant no longer needs nurse- 

 leaves, for it now has green leaves of its own with 

 which to capture carbon dioxide, and its root is 

 branching in all directions in the soil and plenti- 

 fully supplying the necessary sap to manufacture 

 still other leaves. It is true that the leaves have 

 not yet assumed the palmate shape characteristic 

 of the sycamore species, but, nevertheless, each 

 pair now produced gets nearer to the type. 



The little central bud steadily persists in pro- 

 ducing new leaves for a while, and then from its 



22, 



